Device absorbing the energy of impacts of railway cars

ABSTRACT

An energy absorbing device has a rod with a part, suitable for cutting by means of surrounding cutting tools mounted in a body sleeve and oriented to the inside. In addition, the rod has an angular guiding part passing into the part suitable for cutting and is pivoted in a support, wherein the body sleeve with the attached cutting tools is connected by breakable elements with the support.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. §371 ofInternational Application No. PCT/IB2015/059202, filed Nov. 30, 2015,which claims priority of Polish Patent Application No. P.410337, filedDec. 2, 2014, the entire contents of each application being hereinincorporated by reference.

TECHNICAL FIELD

The present invention relates to a device absorbing the energy ofimpacts of railway cars, applicable particularly in railway centralcouplers.

BACKGROUND ART

An impact energy absorption device comprising a rod suitable for cuttingby the surrounding cutting tools arranged uniformly in the body sleeveis known from patent description PL202114. In order to ensure the properguiding of cutting tools, the blades of these tools are placed in guidesformed on the outer surface of the rod.

There is also known from patent description PL 211405 an impact energyabsorption device comprising a rod, with a smoothly varying diameter,suitable for cutting by means of cutting tools. In particular, the rodtakes the form of a conic, pyramid or other curvilinear form to provideincreased energy absorption capacity in the event of collisions of highkinetic energy.

Known devices perform well their tasks at normal collisions, however incase of an increased deviation angle between the cars, striking eachother, some uncontrolled displacements between the body sleeve with thecutting tools and the machined rod occur. Such displacement causes thedeformation of the cooperating parts, which in turn makes impossiblefurther efficient absorption of energy.

SUMMARY OF THE INVENTION

The aim of the invention is to provide an impact energy absorbing devicewith increased resistance to lateral forces which, with its simpleconstruction, would be able to absorb high energy in an emergency suchas collision of railway cars and to protect these cars from damage, inparticular, with increased angular deviations occurring between the carshitting each other.

The device of the invention comprises a rod, a part of which is suitablefor cutting by surrounding cutting tools mounted in a body sleeve andoriented to the inside of the sleeve. The invention is characterized inthat the rod has an angular guiding part passing into a part suitablefor cutting and is pivoted on a support, wherein the body sleeve withthe attached cutting tools is connected to the support by means ofbreakable elements.

Preferably, the angular guiding part of the rod is connected to a lugembedded in holes of the support by an axle perpendicular to the axis ofthe rod.

Preferably, breakable elements are screws with a determined strength.

Preferably, the surface of the angular guiding part is inclined at anangle within the range from 7° to 30° relative to the axis of the rod,more preferably between 11° to 23°, and even more preferably between 12°to 18°.

Preferably, the angular guiding part is conical in shape.

Preferably, the rod has an increasing wall thickness in the angularguiding part.

Preferably, the lug embedded in the holes of the support has acylindrical part intended to be embedded in the slot formed in theangular guiding part of the rod.

Preferably, a hardness of the surface layer of the initial region of theangular guiding part surface is greater than the limit of machinability,wherein the closer to the part of the rod suitable for cutting, thehardness of the surface layer of the angular guiding part decreasesbelow the limit of machinability.

The pivoted fixing of the rod in the support, and the use of breakableelements connecting the body sleeve with the support allows easieralignment of the rod with the contact of its angular guiding part withthe cutting tools mounted in the body sleeve.

By combining the angular guiding part of the rod with the lug swingablyseated in the holes of the support a simple articulation was obtained,providing the rotation of the rod with respect to the body sleeve fittedwith the cutting tools.

The use of the screws with the determined strength as the breakableelements simplifies the construction since the screws are used in thedevice according to the invention at the same time as fasteners andsafety components, determining the limit of the pressure force exertedby the cars on each other, at which the energy absorption by machiningis triggered.

Inclination of the surface of the guiding part at the angle within therange from 7° to 30° relative to the axis of the rod allows efficientalignment of the rod with respect to the body sleeve with cutting tools.Increasing the inclination above the limit of 30° could cause thedriving of the cutting tools into the initial area of the angularguiding part and its deformation, and thereby prevent the displacementof the body sleeve with the cutting tools into the area of the rodintended for cutting.

Increasing the thickness of the walls of the angular guiding part isintended to increase the modulus of rigidity and prevent deformation inthis area.

A cylindrical part of the lug allows its exact axial seating relative tothe rod axis.

Hardening of the outer layer of the initial area of the angular guidingpart is intended to produce the sliding contact of the cutting tools inthis initial area, thereby providing better guidance of the further partof the rod, suitable for cutting, relative to the body sleeve with thecutting tools, and thus, more effective alignment of the rod withrespect to said body sleeve.

BRIEF DESCRIPTION OF DRAWINGS

The invention embodiment is illustrated in the drawing, in which

FIG. 1 shows the device absorbing the energy of impacts of railway carsaccording to the invention at rest, before impact, in a top view with apartial axial section,

FIG. 2 shows the energy absorbing device at rest, in a side view with apartial axial section,

FIG. 3 shows the energy absorbing device in a front view,

FIG. 4 shows the energy absorbing device in perspective view,

FIG. 5 shows the device according to the invention in a top view, suchas in FIG. 1, at the first step of guidance,

FIG. 6 shows the device according to the invention at the final step ofguidance, and

FIG. 7 shows the device according to the invention at the step ofoperation.

DETAILED DESCRIPTION OF EMBODIMENTS

As shown in the embodiment in FIG. 1 and FIG. 2, the device absorbingenergy of impacts of railway cars according to the invention comprises asteel rod 1 with a part 2, suitable for cutting and with an angularguiding part 3, with a surface inclined relative to an axis of the rod 1at an angle of α=15°. The rod 1 is in the form of the sleeve with asubstantially constant thickness in the part 2 suitable for cutting, andin the frustoconical form in the guiding part 3. In addition, the endregion of the guiding part 3 has also a function of the area intendedboth for guiding and for initial cutting. The guiding part 3 has acylindrically formed axial slot 4, in which a cylindrical part 5 of alug 6 is mounted. The said cylindrical part 5 is also welded to the faceof the angular guiding part 3. The execution of the angular guiding part3 in the form of a truncated cone with the cylindrical slot 4 enablesobtaining the increasing thickness of that part as it approaches thepart 2 suitable for cutting. A hole 7 of the lug 6 and holes 8 of thesupport 9 house an axle 10, perpendicular to axis 11 of the rod 1,allowing the pivoted attachment of the lug 6, and thereby the pivotedattachment of the whole rod 1.

The support 9 is fixed to a body sleeve 12 with breakable elements 13 inthe form of screws with a determined tensile strength. Proper selectionof the quantity, diameter and material strength of the screws allows todetermine the limit at which the detachment of the body sleeve 12 fromthe support 9 occurs and, therefore, allows to determine the limit ofenergy existing between the railway cars striking each other, at whichthe step of kinetic energy absorption by cutting is triggered. To thisend, the body sleeve 12 is provided with cutting tools 14 distributedcircumferentially and fixed on its front part. The cutting tools 14 areoriented into the interior of the body sleeve 12, and tips 15 of bladesof these cutting tools 14 are arranged on a smaller diameter than thediameter of the cylindrical part 2 of the rod 1.

In the illustrated embodiment, the rod 1 has an initial part of theangular surface of the guiding part 3 hardened to a value within therange of 45-55 HRC with the hardness of the cutting tools within therange of 58-63 HRC. For the interpretation of the embodiment, as theinitial area of the angular surface of the guiding part 3, the lateralsurface of a truncated cone starting with its smallest diameter andextending to half its height was adopted. The remainder of the angularguiding part 3 has the hardness decreasing as approaching the largestdiameter, wherein from the diameter of the cone corresponding to thediameter of the distribution of the tips 15 of the blades of the cuttingtools 14, the angular surface hardness is the smallest and has a valuewithin the range of 27-30 HRC, also the whole sleeve part 2, suitablefor cutting, has the same hardness.

In another embodiment, in order to increase the progressivity of theabsorption of the kinetic energy of the impact of railway cars, thehardness of the sleeve part 2, suitable for cutting, increases in thedirection of the travel of cutting tools from the hardness within therange of 27-30 HRC to the limit of machinability i.e. 38-43 HRC with thehardness of the cutting tool blades within the range of 58-63 HRC. Thelimit of machinability was adopted as the difference in the hardness ofthe blade of the cutting tool and the hardness of the cut part of 20HRC, therefore, at a blade hardness of 58 HRC, the limit value of thesurface layer of the part suitable for cutting is 38 HRC. A similareffect of increasing the progressivity of the energy absorption can beachieved in the present invention, not shown in the drawing, byincreasing the thickness of the layer being cut along the cutting path,which is obtainable by the use of the sleeve part 2 with an increasingouter diameter in the direction of travel of the cutting tools 14. Thesurface of the angular guiding part 3 can be inclined relative to theaxis 11 of the rod 1 at an angle α within the range from 7° to 30°, butthe best conditions in the majority of cases of the impacts of railwaycars are provided by an angle α=15°.

In another embodiment, not illustrated in the drawing, the angularguiding part 3 has the shape of a truncated pyramid with a square baseand passes into the part 2, suitable for cutting, in the form of asleeve with a square cross section, in which case also the body sleeve12 has a square internal opening allowing loose movements of the wholerod 1 along its axis.

As shown in FIG. 3, the device of the invention has six cutting tools 14distributed at equal angular intervals and mounted by means of screws 16in recesses formed in the front part of the body sleeve 12. Holes 17made symmetrically between the cutting tools 14 are intended for fixingthe body sleeve 12 to the front wall of a railway car.

As shown in FIG. 4, the cutting tool 14 are in the form of knives forcutting, and the tips 15 of these knife blades are directed radiallytowards the centre of the body sleeve 12. Furthermore, at the end partof the sleeve-shaped rod 1 an inner ring 18 is formed increasing therigidity of the structure and at the same time constituting an elementthat facilitates supporting and securing of the rod 1 in the structureof the railway coupling.

FIG. 5 shows the first step of the angular guiding of the rod 1 relativeto the body sleeve 12 with the cutting tools 14. After overrunning thelimit pressure forces of the interconnected railway cars, the rupture ofthe breakable elements 13, in the form of screws with a determinedstrength, occurs so that a screw head 13 a with a portion of its shankremains in the displaced support 9, and a remainder of a threaded shank13 b remains in the body sleeve 12 attached to the front wall of thecar, not shown in the drawing. In this step, the cutting tools 14 pressagainst one side of the angular guiding part 3, causing a generation ofinitial force guiding the rod 1 to an axial position relative to thebody sleeve 12.

FIG. 6 illustrates the final step of the angular guidance of the rod 1relative to the body sleeve 12 with the cutting tools 14. In this step,all the cutting tools 14 are in contact with the angular guiding part 3,however machining of that angular part takes place on one side, whichresults in an increased force, causing the straightening moment, guidingthe rod 1 to the axial position relative to the body sleeve 12.

FIG. 7 shows the device according to the invention at the step ofoperation. In this step, some possible small angular deviations of therod 1 relative to the body sleeve 12 are countered. In this step, allthe cutting tools 14 are involved in the cutting process and substantialabsorption of the kinetic energy of the impact of railway cars. In thecase of non-axial movement of the rod 1 relative to the body sleeve 12,the increased cutting forces, caused by a greater penetration of thecutting tools 14 into the surface layer of the part 2 of the rod 1,suitable for cutting, produce the pressure of those more sunk cuttingtools 14 onto the rod 1, and thus generate a further straighteningmoment affecting the precise alignment of the components advancing eachother.

PARTS LIST FOR FIGS. 1-7

1—rod,

2—part of the rod which is suitable for cutting,

3—angular guiding part,

4—slot,

5—cylindrical part of the lug,

6—lug,

7—lug hole,

8—opening of the support,

9—support,

10—axle,

11—rod axis,

12—body sleeve,

13—breakable elements,

14—cutting tool,

15—tips of the blades of cutting tools,

16—mounting screw of the cutting tool,

17—holes for fixing the body sleeve to the front wall of the railwaycar,

18—inner ring,

α—angle of inclination of the angular guiding part relative to the axisof the rod.

These and other features will be readily apparent from the followingclaims.

1. A device for absorbing energy of impacts of railway cars, comprising:a rod with a part suitable for being cut, cutting tools mounted in abody sleeve and oriented to the inside thereof, the rod having anangular guiding part with a surface inclined relative to an axis of therod, wherein the angular guiding part of the rod is connected with a lugpivotally attached to a support, and the body sleeve with attachedcutting tools is connected to the support by means of breakableelements.
 2. The device according to claim 1, wherein the lug isembedded in openings of the support by an axle situated perpendicularlyto the axis of the rod.
 3. The device according to claim 1, wherein thebreakable elements are screws with a determined strength.
 4. The deviceaccording to claim 1, in which a surface of the angular guiding part isinclined at an angle (α) within the range from 7° to 30° relative to theaxis of the rod.
 5. The device according to claim 1, in which thesurface of the angular guiding part is inclined at the angle (α) withinthe range from 11° to 23° relative to the axis of the rod.
 6. The deviceaccording to claim 1, in which the surface of the angular guiding partis inclined at the angle (α) within the range from 12° to 18° relativeto the axis of the rod.
 7. The device according to claim 1, in which theangular guiding part has a conical shape.
 8. The device according toclaim 1, in which the rod has a sleeve form.
 9. The device according toclaim 8, wherein the rod has an increasing wall thickness in the angularguiding part.
 10. The device according to claim 2, in which the lug hasa cylindrical part configured to be embedded in a slot formed in theangular guiding part of the rod.
 11. The device according to claim 1, inwhich the hardness of a surface layer of an initial region of theangular guiding part is greater than the limit of machinability, whereinthe closer to the part suitable for being cut, the hardness of thesurface layer of the angular guiding part decreases below themachinability limit.